Effect of iron-doped multi-walled carbon nanotubes on lipid model and cellular plasma membranes

The aim of the present work was the study of the interaction of multi-walled carbon nanotubes filled with iron (Fe-MWCNTs) with bimolecular lipid model membrane (BLM) and cellular plasma membrane (PM). The findings demonstrate that the Fe-MWCNTs adsorb on the BLM surface with possible partial build up in the hydrophobic area of fatty acid residues of lipids and increase its specific conductivity and capacity. Furthermore, upon interaction with the PM, the Fe-MWCNTs form channels which allow the flow of water to the cells and the externalization of phosphatidylserine from the inner to the outer PM leaflet.

Characteristics of "Tip-DCs and MDSCs" and Their Potential Role in Leishmaniasis

Since the first description of dendritic cells (DCs) by Steinman and Cohn (1973), the myeloid lineage of leukocytes was investigated intensively. Nowadays it is obvious that myeloid cells, especially DCs, are crucial for the adaptive and innate immune response against intracellular pathogens such as Leishmania major parasites. Based on the overlapping expression of molecules that were commonly used to classify myeloid cells, it becomes difficult to denominate those cell types precisely. Of note, most of these markers used for myeloid cell identification are expressed on a broad range of myeloid cells, and should therefore be handled with care if used for subtyping of myeloid cells. In this mini-review we aim to discuss the relative impact of DCs that release TNF and nitric oxide (Tip-DCs) and myeloid cells with suppressive capacities (myeloid-derived suppressor cells, MDSCs) in infectious diseases such as experimental leishmaniasis. In our point of view it cannot be excluded that the novel subsets that were denominated as “Tip-DCs” and “MDSCs” might not be classical “subsets” but rather represent myeloid cells in a transient maturation stage expressing different genes, in response to the surrounding environment.

Leishmania major parasite stage-dependent host cell invasion and immune evasion

Leishmania pathogenesis is primarily studied using the disease-inducing promastigote stage of Leishmania major. Despite many efforts, all attempts so far have failed to culture the disease-relevant multiplying amastigote stage of L. major. Here, we established a stably growing axenic L. major amastigote culture system that was characterized genetically, morphologically, and by stage-specific DsRed protein expression. We found parasite stage-specific disease development in resistant C57BL/6 mice. Human neutrophils, as first host cells for promastigotes, do not take up amastigotes. In human macrophages, we observed an amastigote-specific complement receptor 3-mediated, endocytotic entry mechanism, whereas promastigotes are taken up by complement receptor 1-mediated phagocytosis. Promastigote infection of macrophages induced the inflammatory mediators TNF, CCL3, and CCL4, whereas amastigote infection was silent and resulted in significantly increased parasite numbers: from 7.1 ± 1.4 (after 3 h) to 20.1 ± 7.9 parasites/cell (after 96 h). Our study identifies Leishmania stage-specific disease development, host cell preference, entry mechanism, and immune evasion. Since the amastigote stage is the disease-propagating form found in the infected mammalian host, the newly developed L. major axenic cultures will serve as an important tool in better understanding the amastigote-driven immune response in leishmaniasis.

Using C60 fullerenes for photodynamic inactivation of mosquito iridescent viruses

This article describes the photodynamic inactivation of mosquito iridescent virus (MIV) Aedes flavescens in the presence of water-soluble C(60) fullerenes. It has been observed that the photodynamic inactivation of MIV for about 1 h reduces the infectious titre of the virus in large wax-moth larvae Galleria mellonella to 4.5 lg ID(50)/mL. The influence of the C(60) concentration on its anti-viral activity was tested in the concentration range from 1 to 0.001 mg/mL. It has been found that C(60) is able to inactivate the iridovirus even in low concentrations. Consequently, the findings of this work suggest that photoexcited C(60) fullerenes can be successfully used for the inactivation of iridoviruses in biological systems.

Pristine C(60) fullerenes inhibit the rate of tumor growth and metastasis

AIM

To estimate the impact of C(60) fullerene aqueous solution (C(60)FAS) on the rate of transplanted malignant tumor growth and metastasis.

METHODS

Lewis lung carcinoma was transplanted into С57Bl/6J male mice. Conventional methods for the evaluation of antitumor and antimetastatic effects have been used.

RESULTS

The C(60)FAS at low single therapeutic dose of 5 mg/kg inhibited the growth of transplanted malignant tumor (antitumor effect) and metastasis (antimetastatic effect): the maximum therapeutic effect was found to be of 76.5% for the tumor growth inhibition; the increase of animal life span by 22% was found; the metastasis inhibition index was estimated as 48%.

CONCLUSION

It was found that water-soluble pristine С(60) fullerenes efficiently inhibit the transplanted malignant tumor growth and metastasis.

Using water-soluble C60 fullerenes in anticancer therapy

Growth experiments of transplanted malignant tumors in the presence of water-soluble C₆₀ fullerenes were performed on groups of mice. It was found that C₆₀ fullerenes efficiently inhibit the growth of transplanted malignant tumors. This behavior can be explained through their high antioxidant activity and the blocking of the specific cell receptors (for example, endothelial growth factor). The findings demonstrate the possibility of using C₆₀ fullerenes in anticancer therapy.

Low-temperature 1H-NMR spectroscopic study of doxorubicin influence on the hydrated properties of nanosilica modified by DNA

The effect of the anticancer drug--doxorubicin (Dox) on hydration properties of a nanocomposite material deposited on silica and modified by small amount of DNA (0.6 wt%) was studied by means of (1)H NMR spectroscopy at low temperatures (in the range of 200-280 K). Signals of either weakly (WAW) or strongly (SAW) associated water, as well as water associated with electrondonor groups of the composite surface (ASW), were observed. The findings reveal that, depending on the temperature and the composition of the dispersion medium, fast molecular exchange takes place between different forms of interphase water. The presence of Dox (0.1-0.2 wt%) in the dispersion medium leads to change of the relative concentrations of different forms of water.

Hyperthermic effect of multi-walled carbon nanotubes stimulated with near infrared irradiation for anticancer therapy: in vitro studies

It is proposed to use the novel paradigm of treating cancer with hyperthermic therapy using multi-walled carbon nanotubes (MWCNT) stimulated with near infrared (NIR) irradiation.

AIM

To establish the capacity of MWCNT stimulated with NIR irradiation to destroy Erlich ascitic carcinoma (EAC) cells.

MATERIALS AND METHODS

EAC cells suspension was irradiated with NIR heating lamp with a wavelength of 0.78-1.40 mm and power density of 3.5 W/cm2 over 1.5 min in the presence of MWCNT (0.1 mg/ml). The changes in the temperature of suspension with the NIR exposure time was measured using the differential cooper-constantan thermocouple. The viability of EAC cells was evaluated by trypan blue staining.

RESULTS

The death of 95.2% of EAC cells in the presence of MWCNT was observed after 1.5 min of NIR light irradiation: thermal ablation temperature was approximately 50 degrees C.

CONCLUSIONS

It was demonstrated that addition of MWCNT to EAC cell suspension results in the photo-ablative destruction of cells exposed to short time NIR irradiation.

Are neutrophils important host cells for Leishmania parasites?

Neutrophils are the most crucial cells for early defence against infections. When appropriately activated, they can kill obligate intracellular pathogens such as Leishmania. However, once the phagocytotic killing has been evaded, neutrophils can serve as host cells for Leishmania. Parasitized neutrophils were suggested to function as a 'Trojan horse', to transfer Leishmania silently to macrophages. In vivo imaging has contributed a second evasion mechanism. We termed it the 'Trojan rabbit' strategy, whereby parasites escape dying neutrophils to infect macrophages. Here, we discuss the different experimental models used to study neutrophil function in leishmaniasis. We suggest that the capacity of neutrophils to function as an immune evasion target depends on the genetic background of the host and the parasite strain used for the experiments.

Priming of CD8+ and CD4+ T cells in experimental leishmaniasis is initiated by different dendritic cell subtypes

The biological role of Langerin+ dendritic cells (DCs) such as Langerhans cells and a subset of dermal DCs (dDCs) in adaptive immunity against cutaneous pathogens remains enigmatic. Thus, we analyzed the impact of Langerin+ DCs in adaptive T cell-mediated immunity toward Leishmania major parasites in a Lang-DTR mouse model that allows conditional diphtheria toxin (DT)-induced ablation of Langerin+ DCs in vivo. For the first time, infection experiments with DT-treated Lang-DTR mice revealed that proliferation of L. major-specific CD8+ T cells is significantly reduced during the early phase of the immune response following depletion of Langerin+ DCs. Consequently, the total number of activated CD8+ T cells within the draining lymph node and at the site of infection is diminished. Furthermore, we show that the impaired CD8+ T cell response is due to the absence of Langerin+ dDCs and not Langerhans cells. Nevertheless, the CD4+ T cell response is not altered and the infection is cleared as effectively in DT-treated Lang-DTR mice as in control mice. This clearly demonstrates that Langerin+ DCs are, in general, dispensable for an efficient adaptive immune response against L. major parasites. Thus, we propose a novel concept that, in the experimental model of leishmaniasis, priming of CD4+ T cells is mediated by Langerin- dDCs, whereas Langerin+ dDCs are involved in early priming of CD8+ T cells.